Automatic strip threading devices



3 Sheets-Sheet 1 Filed July 29, 1960 m mm D Sept. 7, 1965 D. LYLE 3,204,441

AUTOMATIC STRIP THREADING' DEVICES Filed July 29, 1960 a Sheets-Sheet 2 Fig.2.

INVENTOR Dovid Lyle M Sept. 7, 1965 D. LYLE AUTOMATIC STRIP THREADING DEV ICES 3 Sheets-Sheet 5 Filed July 29, 1960 INVENTOR David Lyle United States Patent 3,204,441 AUTOMATIC STRIP THREADING DEVICES David Lyle, Mount Lebanon, Pa., assignor to Blaw-Knox Company, Pittsburgh, Pa., a corporation of Delaware Filed July 29, 1960, Ser. No. 46,148 13 Claims. (CI. 72-31) This invention relates to an automatic strip threading device and particularly to automatic strip threading systems for tandem rolling mills.

In the production of strip on tandem mills the threading of the strip has been a continuous problem. In order to produce satisfactory commercial strip, the tandem mill must be threaded with the strip tracking on a straight line through the mill.

The difficulty encountered in threading the tandem mill necessitates relatively slow and laborious manual efforts to accomplish the desired condition for tracking on a straight line through the tandem mill. These difficulties arise largely from non-uniform conditions of the strip and non-uniform conditions encountered in the mill stands.

Moreover, the operating mechanisms of prior mills are not sensitive to the behavior of the strip passing through the mills.

I have invented an apparatus and a method of automatically threading tandem rolling mills which eliminates the problems heretofore facing this segment of the industry. I provide a system which makes possible automatic strip threading through tandem mills.

In a preferred embodiment of my invention, I provide in a tandem rolling mill having spaced mill stands in series, an entry conveyor adapted to deliver coils to be processed towards the mill, centering guides on opposite sides of the coil conveyor adapted to center the coil with respect to the center line of the tandem mill, transfer means for receiving the centered coil from the conveyor and to carry the coil along the center line of the mill, coil opener means adapted to peel and to straighten the leading end of the strip from the coil, coil holding means receiving the coil from the transfer means, shifting means acting on the coil carrying means for transversely shifting the coil with respect to the mill center line, strip end supporting means, strip end feeding means, sensing means on the path of strip travel adapted to actuate the shifting means when the strip moves out of the mill center line whereby to center the strip back on the mill center line, guide means directing the strip lead end into the first mill roll stand, a guide means between each adjacent mill stand receiving the strip lead end from the preceding mill stand for guiding the strip to the following mill stand, said guide means having on opposite sides of the path of strip travel a large end open to receive the end of the moving strip from said preceding mill stand and tapering to a small end directed toward the opening of said following mill stand, sensing means on each of said guide means adapted to be actuated by the strip when the strip deviates out of the mill centerline and drive means actuated by the sensing means acting on the said preceding mill stand to difierentially vary the roll pressure across the strip.

In the foregoing general description, I have set out certain objects, purposes and advantages of my invention. Other objects, purposes and advantages will be apparent from the following description and the accompanying drawings in which,

FIGURE 1 is a top plan view of a portion of a tandem mill line incorporating my invention;

FIGURE 2 is a vertical section on the center line of the mill of FIGURE 1;

FIGURE 3 is an enlarged top plan view of the guide means between adjacent mill and stands;

FIGURE 4 is a section on the line IV-IV of FIGURE 3; and

FIGURE 5 is a view partly in section on the line V-V of FIGURE 3.

Referring to the drawings, a coil of strip 10 is delivered to the tandem mill on a coil conveyor 1011. A pair of centering guides 11 is provided adjacent the delivery end of the coil conveyor 10a. The centering guides 11 are moved toward and away from one another by a suitable means such as a hydraulic cylinder 12. The centering guides 11 and cylinder 12 act on the coil to center the coil with respect to the center line of the tandem mill. The centered coil 10 is then advanced to cradle 13 mounted on an elevator 14 on coil car 15 driven along the mill centerline by suitable means such as a hydraulic cylinder or a rack and pinion drive 15a, which carries the coil to a coil opener 16 which may be as illustrated of a peeler blade type. Rollers 17a and 17b on the cradle 13 are driven in conventional manner to rotate the coil 10 against the blade and roller of the opener 16 to peel the leading end of the strip away from the coil a sufficient distance and to straighten the leading end for threading purposes. The coil opener 16 is then retracted transversely by suitable means such as cylinder 16a. The straightened end of the coil is fed between the then opened pinch rolls 19 by rotating the coil by means of the rollers 17a and 17b, and rests on shelf-type sideguards 18a located above the mill passline. Said sideguards are equipped with a quickopening device to drop the then straightened leading end of the strip to the passline level immediately after the tail end of the preceding coil has been paid-oh. Coil 10 is then advanced into the coil box 18 by lifting cradle roller 17b and lifting the cradle roller 18b, thereby transferring the coil without rolling from the cradle 13 onto the coil box cradle rollers 18b and 180 by fiinally lowering cradle roller 18b. The foregoing transfer of the coil without rolling is accomplished by raising the cradle roller 1811 by means of the hydraulic cylinder and piston 18d about the axis of the roller 180. This brings the roller 18b substantially directly above the roller 18c. Lifting the roller 1717 by means of the hydraulic cylinder immediately below it, moves the coil against roller 18b by a'simple rocking movement about the roller 17a without any rolling of the coil from one position to another, the coil then being held between the raised rollers 17b and 18b. The coil then follows the roller 18b down on 18c as the roller 18b is lowered. The coil unwinds slightly as it is lowered by the roller 1812. However this is not due to any rotation of the roller 17b or 1811 causing the coil to rotate but simply the drawing away of the outer wrap as the center moves to the left viewing FIG- URE 2. In the meantime, when the tail end of the pre- 30b and 31b to form a bellmouth guide.

ceding strip has gone through the pinch roll and the then straightened end of the succeeding coil has been dropped to the passline, the pinch rolls are closed and begin to deliver the strip to the first mill stand.

The coil box 18 is automatically positioned transversely by means of hydraulic cylinder 20 being controlled by intelligence from a sensing unit 21 to maintain coil 10 on the mill center line as preset by automatic motor centering operation for varying strip widths of guides 22.

The leading end of coil 10 upon leaving the first mill stand passes into the interstand threading guide in which is included tensiometer 28 of conventional design. The sideguards 30 and 31 are preset by automatic motor centering operation for varying strip widths the same as guides 22 were set as previously indicated. Each of the sideguards 30 and 31 is in the form of a V-shaped channel with the large ends 30a and 31a open to receive the leading end of the strip and converging to the opposite ends Each of sideguards 30 and 31 is mounted on housings 30c and 31c adjusted toward and away from the other by means of motor 32, acting through gears 33 on screws 34 and 35 having opposite threads extending transversely of the path of strip travel and upon which the sideguards 30 and 31 are mounted. Rotation of the screws 34 and 35 causes the sideguards 30 and 31 to move with respect to one another but always equidistant from the mill center line. Between the flanges 30a, 30b and 3111, are provided a plurality of vertical rollers 36, leading into guide rollers 46. The sideguards 30 and 31 as preset are then in position to receive the leading end of the coil with cylinders 37 mounted on the sideguard housings and attached to each sideguard. Cylinders 37 are maintained under predetermined pressure holding the sideguards at the preset position unless the leading end of the coil 10 deviates from the mill center line. Such deviation of the strip moves the sideguard 30 or 31 laterally from the center line of the mill as the case may be. Suitable detectors 38 are mounted on each of the sideguard housings 30c and 310 and are attached to each sideguard. Such detector may be, for example, a variable transformer type of detector in which the windings of the transformer are mounted on the housings 30c and 31c and the movable core is attached to the sideguards 30 and 31. The output of this variable transformer detector is passed through an amplifier 39 to a controller 40 which acts on motive devices 41 to drive racks 41a. Racks 41a in turn act on gear segments 42 attached to the screwdowns of the mill. Thus, whenever the leading end of coil 10 deviates from the mill center line so as to cause a corresponding movement of the transformer core of the variable transformer, this corresponding deviation is passed through the amplifier 39 and controller 40 causing the racks 41a to move appropriately to vary the pressure of the rolls on the edges of the strip thereby causing the strip to return to the center line of the mill.

The controller 40 is programmed in such a manner that the magnitude of the deviation will determine whether one or both motive devices 41 will be actuated.

Load cells 43 are placed beneath each mill screw to provide a signal of pressure between the rolls of each stand. The signal of these load cells is utilized for various operations. Among these the load cells provide an instrumentality to operate the motors 32 or the cylinders 37 and the cylinder 46b at the instant the strip enters or leaves the mill stands. As the strip leaves each mill stand, the signal given by the load cell resets controller 40 to the initial setting of each stand preparatory to threading a new coil.

Referring particularly to the operation of the sideguards from the load cells mentioned above, it is intended that upon the front end of the strip entering a succeeding stand 24 after going through the sideguard 30 or 31, a signal from the load cells incorporated in the succeeding stand 24 will give cause for the above-mentioned sideguards to move away from the previously preset position; and conversely, upon the tail end of the strip leaving the roll stand 24, a signal from the load cells incorporated in said stand will again give cause for movement of the sideguard 30 or 31 back into the previously preset width position corresponding to the strip width being rolled. The circuits from the load cells which actuate the controller 40 and the sideguard actuator are conventional and well known. They may take any of the forms shown, for example, in Capuzzi Patent No. 2,550,527, Ruge Patents Nos. 2,561,317, 2,688,727, and 2,423,620, MacGeorge Patent No. 2,531,228, Schaevitz Patent No. 2,548,397, Gibbons Patent No. 2,472,045 or Simmons Patent No. 2,362,589, or any other of the known variants of such circuits, all of which have been used for similar purposes.

The interstand threading guide frame 29 is mounted on a hydraulic cylinder 45 situated below mill floor level. Cylinder 45 permits the guide frame to be lowered out of the path of strip travel to permit easy access to mill utilities. In addition, the guide frame is arranged to retract in its entirety laterally from the mill center line for maintenance purposes. There is provided an identical guide frame 29 with accessory parts between each stand as described hereinabove.

All operations herewith described are arranged for automatic sequence operation.

In the foregoing description, I have set out certain preferred embodiments and practices of my invention. However, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

1. In a tandem mill assembly having spaced mill stands in series on a center line, work rolls in each said mill stand, conveyor means adapted to convey a coil along said center line, centering guides on opposite sides of the coil conveyor means adapted to center the coil with respect to the center line of the mill, transfer means receiving the centered coil from the coil conveyor carrying the coil without significant rotation parallel to the center line, coil opener means adapted to peel and straighten the leading edge of the strip from the coil, coil holding means receiving the coil from the transfer means, shifting means acting on the coil carrying means for transversely shifting the coil with respect to the passline, sensing means on the path of strip travel adapted to actuate the shifting means when the strip moves out of the mill center line whereby to center the strip on the center line, guide means directing the strip end into the first roll stand, a threading guide vertically movable between the work rolls of each adjacent mill stand receiving the strip end from the Work rolls of one mill stand for transfer to the work rolls of the next adjacent mill stand, guide means movable on saidthreading guide transversely to the mill center line on opposite sides of the path of strip travel having a large end open to receive the end of the moving strip from said one mill and tapering to a small end directed toward the opening of said next adjacent mill stand, actuating means on the threading guide simultaneously moving said guide means relative to the mill center line to bring the guide means into preset guiding position with respect to the strip edges, sensing means on each of said guide means adapted to be moved by the strip when the strip deviates out of the mill center line and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the stand whereby to center the strip on the mill center line.

2. In a tandem mill structure as claimed in claim 1, a pressure responsive means on each said mill stand acting on the actuating means on the threading guide preceding said mill stand to open said guide means after the lead strip end enters said mill stand.

3. In a tandem mill assembly having spaced mill stands in series on a mill center line, work rolls in each said mill stand, conveyor means adapted to convey a coil along said center line, centering guides on opposite sides of the coil conveyor means adapted to center the coil with respect to the center line of the mill, transfer means receiving the centered coil from said coil conveyor carrying the coil without significant rotation parallel to the center line, coil opener means adapted to peel and straighten the leading edge of the strip from the coil, coil holding means receiving the coil from the transfer means, shifting means acting on the coil carrying means for transversely shifting the coil with respect to the center line, sensing means on the path of strip travel adapted to actuate the shifting means when the strip moves out the center line whereby to center the strip on the center line, guide means directing the strip end into the first roll stand, a threading guide vertically movable between each adjacent mill stand receiving the strip end from one mill stand for transfer to the next adjacent mill stand, guide means on said threading guide on opposite sides of the path of strip travel having a large end open to receive the end of the moving strip from said one mill and tapering to a small end directed toward the opening of said next adjacent mill stand, roller means on said guide means resiliently bearing on the strip edges to guide the strip through the guide means, sensing means on each of said guide means adapted to be energized by the strip when the strip deviates out of the center line and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the tand whereby to center the strip in the threading guide.

4. In a tandem mill structure as claimed in claim 3 wherein the sensing means on the threading guide is a variable transformer having a moving core mounted on the guide means and movable with respect to a coil fixed to the threading guide.

5. In a tandem mill assembly having spaced mill stands in series on a mill center line, a threading guide vertically movable between the work rolls of each adjacent mill stand receiving the strip end from the work rolls of one mill stand for transfer to the work rolls of the next adjacent mill stand, guide means movable on said threading guide transversely to the center line on opposite sides of the path of strip travel having a large end open to receive the end of the moving strip from said one mill and tapering to a small end directed toward the opening of said nex-t adjacent mill stand, actuating means on the threading guide simultaneously moving said guide means relative to the mill center line .to bring the guide means into preset guiding position with respect to the strip edges, sensing means on each of said guide means adapted to be moved by the strip when the strip deviates out of the center line and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the stand whereby to center the strip on the mill center line.

6. In a threading guide structure as claimed in claim 5, a pressure responsive means on each said mill stand acting on the actuating means on the threading guide preceding said mill stand to open said guide means after the lead strip end enters said mill stand.

7. In a tandem mill assembly having spaced mill stands in series on a center line, work rolls in each said mill stand, conveyor means adapted to convey a coil along said center line, centering guides on opposite sides of the coil conveyor means adapted to center the coil with respect to the center line of the mill, transfer means receiving the centered coil from said coil conveyor and carrying the coil without substantial rotation parallel to the mill center line, coil opener means adapted to peel and straighten the leading end of the strip from the coil, coil holding means receiving the coil from the transfer means, shifting means acting on the coil holding means for transversely shifting the coil with respect to the mill center line, sensing means on the path of strip travel adapted to actuate the shifting means when the strip moves out of the mill center line whereby to center the strip on the mill center line, guide means directing the strip end into the first roll stand, a threading guide between the work rolls of each adjacent mill stand receiving the strip end from the work rolls of one mill stand for transfer to the work rolls of the next adjacent mill stand, guide means on said threading guide on opposite sides of the path of strip travel having a large end open to receive the end of the moving strip from said one mill stand and tapering to a small end directed toward the opening of said next adjacent mill stand, sensing means on each of said guide means adapted to be moved by the strip when the strip deviates out of the center line and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the stand whereby to center the strip on the mill center line.

8. In a tandem mill assembly having spaced mill stands in series on a center line, work rolls in each said mill stand, conveyor means adapted to convey a coil of strip .6 along said center line, centering guides adjacent the entry end of the first of said spaced mill stands and on opposite sides of the coil conveyor means receiving a coil from the conveyor means and centering the coil on the center line of the mill, transfer means receiving the centered coil from the coil conveyor and-carrying the coil centered on the center line, coil opener means acting on the coil to peel and straighten the leading end of the strip while the strip is in the transfer means, coil holding means receiving the coil from the transfer means While acting with the transfer means to hold the coil centered on the mill center line, shifting means acting on the 'coil holding means selectively shifting the coil transversely with respect to the coil center line after the coil is in the coil holding means, sensing means on the path of strip travel adapted to actuate the shifting means when the strip moves out of the mill center line whereby to maintain the strip entering the line centered on the mill center line, a threading guide spaced between each "adjacent stand of work rolls, sensing means on said threading guide sensing deviation of the strip from the center line of the mill between said adjacent stands, and drive means actuated by the sensing means acting on the first of said adjacent stands to differentially change the roll pressure on opposite sides of the stand whereby to center the strip on the mill center line.

9. In a tandem mill assembly having spaced mill stands in series on a center line, work rolls in each said mill stand, conveyor means adapted to convey a coil of strip along said center line, centering guides adjacent the entry end of the first of said spaced mill stands and on opposite sides of the coil conveyor means receiving a coil from the convey-or means and centering the coil on the center line of the mill, transfer means receiving "the centered coil from the coil conveyor andcentering guides and carrying the centered coil on the center line, coil opener means lifting the leading end of the coil from said coil, coil holding means receiving the cell from the coil transfer means while maintaining the coil centered on the mill center line, shifting means acting on the coil holding means selectively shifting the coil holding means transversely with respect to the strip center line, sensing means on the path of strip travel in advance of the first mill stand adapted to actuate the shifting means to maintain the strip entering the mill stands on the center line, a sensing means between each successive pair of mill stands in the mill assembly, a drive means on each mill stand actuated by the next succeeding sensing means to differentially change the roll pressure on opposite sides of the mill stand whereby to center the strip entering the next succeeding stand on the mill center line.

10. A tandem mill as claimed in claim 9 wherein pressure sensitive means are provided on each mill stand acting to energize the drive means to open and close the work rolls responsive to pressure on the rolls.

11. In a tadem mill assembly having spaced mill stands in series on a mill center line plane, a threading guide vertically movable between the work rolls of each adjacent mill stand receiving material from the work rolls of one mill stand for transfer to the work rolls of the next adjacent mill stand, guide means movable on said threading guide transversely to the center line plane on opposite sides of the path of the material receiving the material from said one mill directing said material toward the opening between the work rolls of said next adjacent mill stand, actuating means on the mill assembly simultaneously moving said guide means relative to the mill center line plane to bring the guide means into preset guiding position with respect to the material edges, sensing means on said assembly actuated by the material when the material deviates out of a predetermined position and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the stand whereby to center the material on the mill center line plane.

12. In a tandem mill assembly having spaced mill stands in series on a center line plane, Work rolls in each said mill stand, conveyor means adapted to convey a coil along said center line, centering guides on opposite sides of the coil conveyor means adapted to center the coil with respect to the center line of the mill, transfer means receiving the centered coil from the coil conveyor carrying the coil without significant rotation in said center line plane, coil opener mean adapted to peel and straighten the leading edge of the material from the coil, coil holding means receiving the coil from the transfer means, shifting means acting on the coil carrying means for transversely shifting the coil with respect to said center line plane, sensing means on the path of material travel adapted to actuate the shifting means when the material moves out of a predetermined position whereby to position the material in the predetermined position, guide means directing the strip end into the first roll stand, a threading guide vertically movable between the work rolls of each adjacent mill stand receiving the material end from the work rolls of one mill stand for transfer to the work rolls of the next adjacent mill stand, guide means movable on said mill assembly transversely to the mill center line plane on opposite sides of the path of the travelling material receiving the moving material from said one mill and directing it toward the opening between the work rolls of said next adjacent mill stand, actuating means on the mill assembly simultaneously moving said guide means relatively to the mill center line plane to bring the guide means into present guiding position with respect to the material edges, sensing means on said mill assembly actuated by the moving material when the strip deviates out of a predetermined position and drive means actuated by the sensing means acting on the said one mill stand to differentially change the roll pressure on opposite sides of the stand whereby to center the material in the predetermined position.

13. A threading device for a tandem rolling mill comprising a series of rolling mill stands on a center line plane, work rolls in each mill stand, threading guide means between the work rolls of adjacent mill stands vertically movable between a position remote from the center line plane and a position on the center line plane receiving a material to be threaded from the work rolls of one mill stand for transfer to the work rolls of the next succeeding adjacent stand, side guide means between said adjacent stands movable transversely to the center line plane on opposite sides of the path of the material to be threaded, first actuating means moving the threading guide into and out of a contact position with the material on the pass line, a second actuating means moving the side guide means relatively to said center line plane into preset guiding position prior to threading material into the mill and moving the guide means away from the threaded material when the material is threaded between said adjacent mills and means at said stands responsive to entry and exit of material from between the rolls energizing said first and second actuating means.

References Cited by the Examiner UNITED STATES PATENTS 2,289,410 7/42 Dahlstrom -56.2 2,331,246 10/43 Stoltz 8051 2,389,443 11/45 Lyle 2427 9 2,558,761 7 51 Kentis 24279 2,651,955 9/53 Fisher 8051 2,75 6,943 7/ 5 6 Seiger 2479 2,815,111 12/57 Capps et al. 19829 2,871,013 1/59 Markey 24257.1 2,961,901 11/60 Wheeler 8056.2

WILLIAM J. STEPHENSON, Primary Examiner.

THOMAS E. BEALL, LEON PEAR, ROBERT F.

WHITE, Examiners. 

11. IN A TADEM MILL ASSEMBLY HAVING SPACED MILL STANDS IN SERIES ON A MILL CENTER LINE PLANE, A THREADING GUIDE VERTICALLY MOVABLE BETWEEN THE WORK ROLLS OF EACH ADJACENT MILL STAND RECEIVING MATERIAL FROM THE WORK ROLLS OF ONE MILL STAND FOR TRANSFER TO THE WORK ROLLS OF THE NEXT ADJACENT MILL STAND, GUIDE MEANS MOVABLE ON SAID THREADING GUIDE TRANSVERSELY TO THE CENTER LINE PLANE ON OPPOSITE SIDES OF THE PATH OF THE MATERIAL RECEIVING THE MATERIAL FROM SAID ONE MILL DIRECTING SAID MATERIAL TOWARD THE OPENING BETWEEN THE WORK ROLLS OF SAID NEXT ADJACENT MILL STAND, ACTUATING MEANS ON THE MILL ASSEMLBY SIMULTANEOUSLY MOVING SAID GUIDE MEANS RELATIVE TO THE MILL CENTER 